REPAIR AND RESTORATION OF THE SR-400
11
WDØGOF 6/22/20014
2-4. RECEIVER FAULT ISOLATION CHART
Injection point
Frequency Signal
injection
level
Audio
output
If good go to next step. If not check suggestions below.
1
V15 pin 7
1000 Hz
14 vpp
1:1 probe
½ wt.
Problem most likely V15 or associated circuitry.
See section 4-2 for details.
2
V9B pin 2
1000 Hz
0.6 vpp
1:1 probe
½ wt.
Problem is most likely V9B or associated circuitry.
See section 4-3 for details.
3
V9A Pin 7
1650 KHz 5000 uv
½ wt.
Problem is most likely V9A or associated circuitry.
See section 4-4 for details.
4
*
V7A Pin 2
1650 KHz 425 uv
½ wt.
Problem is most likely V7A or associated circuitry.
See section 4-5 for details.
5
Tie point
C54/C59
1650 KHz 5000 uv
1:1 probe
½ wt.
Problem is most likely xtal filter or notch filter.
See section 4-6 for details.
6
V6 pin 1
1650 KHz 35 uv
½ wt.
Problem is most likely V6 or associated circuitry.
See section 4-7 for details.
7
V4A Pin 2
6.250
MHz
100 uv
½ wt.
Problem is most likely V4A or associated circuitry.
See section 4-8 for details.
8
@
V3A Pin 2
6.250
MHz
15 uv
½ wt.
Problem is most likely V3 A or B or associated
circuitry. See section 4-9 for details.
9
#
V2A Pin 9
7.250
MHz
8 uv
½ wt.
Problem is most likely V2A or associated circuitry.
See section 4-10 for details.
10
~
Junction
C15&C20
7.250
MHz
6 uv
½ wt.
Problem is most likely 6.5 MHz traps, S1F, V18 grid or
associated circuitry.
11
V1 pin 1
7.250
MHz
0.5 uv
½ wt.
Problem is most likely V1 or associated circuitry.
See section 4-11 for details.
12
$
Tie point S1D
wiper and 6.25
trap
7.250
MHz
0.5 uv
½ wt.
Problem is most likely S1D, S1C, or associated
circuitry.
13
**
J1 direct from
sig. generator
7.250
MHz
0.5 uv
½ wt.
Problem is most likely K1, 6.25 MHz trap, L17 or
associated circuitry.
Upon successful completion to
this point leave all equipment set as they are for
AGC test in next section.
* May require peaking of T3 @ May require peaking of T2
# may require peaking of T1 ~ May require peaking of L10 and PRESELECTOR
$ May require peaking of L3 and PRESELECTOR
** If the RX is working at this point perform
the 6meg trap alignment. See section 8-12.
